Oscillating code transmitter



June 20, 1944. o, s, FIELD I 2,351,588

OSCILLATING CODE TRANSMITTER Filed Dec. 12, 1940 BY I Patented June 20, 1944 OSCILLATING CODE TRANSMITTER Oscar S. Field, Rochester, N. Y., assignor to General Railway Signal Company,

Rochester,

Application December 12, 1940, Serial No. 369,862

3 Claims.

This invention relates to apparatus for intermittently closing a circuit, which may for convenience be called a coder, and relates more specifically to a coder of the oscillatory type.

In railway signalling of either the wayside signal or the cab signal type it has been found desirable to employ coded currents in the track circuit'and in line wires for two reasons, (1) to reduce the total number of line wires along the railway track; and (2) to permit currents of a plurality of distinctive characters and of the same frequency to be inductively transmitted from the track rails to the moving vehicle. The necessary coding has heretofore been accomplished by coders of both the rotary driven type and of the oscillatory type, and the present invention relates particularly to an improvement of coders of the oscillatory type.

In accordance with the present invention it is proposed to provide a coder of the oscillatory type, including a balance wheel supported on a vertical shaft and suitable spring means for biasing the balance wheel to a predetermined position, which is maintained in oscillatory operation by an electro-magnet. In order to improve the efiiciency of the coder as much as practicable it is proposed to employ cams which engage roller for operating both the interrupter contact and the code creating contacts. As another feature of the present invention it is proposed to associate these cams with the contacts which they control in such a manner that a minimum amount of energy is required to operate the contacts, and also so that these cams cannot exert a returning force on the shaft to any appreciable extent to change the oscillatory motion of the balance Wheel from a substantially pure sine motion. Another feature of thepresent invention resides in the provision of a radius arm which may be bearing losses to a minimum. Another feature of the present invention resides in the provision of open rings which may be passed around the shaft and fastened upon the balance wheel to change the moment of inertia of this balance wheel about the 'axisof the shaft, and to provide fastening meansenabling these ring to be fastened in a plurality of different ways so as to allow the slot of one ring to be offset by the slots of one or more other rings.

Other objects, purposes and characteristic features of the invention will in part be pointed out radius arm;

i insulating material.

ably made of brass.

Fig. 4 shows the upper thrust bearing and the lower thrust bearing in cross section; and

Fig. 5 illustrates the circuit connections for one circuit arrangement in which the oscillatory coder of the present invention may be employed.

Referring to Fig. 1 of the drawing the base plate I is preferably constructed of suitable mouldable This base plate may be of general square, circular, or other form provided with a notched external edge on which may be placed a gasket 2 on which the glass casing 3 of square tube-like or cylindrical structure constituting the side walls may rest. On top of this glass casing 3 and a gasket 2 is supported the top plate 4 also preferably constructed of moulded insulating material, into which plate the poles 5 and 6 of magnetic material are suitably moulded. It will be seen that the poles 5 and 6 structure for supporting the mechanism from the top plate 4.

0n the top face of the mid-portion of the U- shaped strap 8 is secured the lower'thrust bearing In in any suitable way as by means of screws II. In a similar way a similar thrust bearing I2 is mounted on the top face of the top plate 4 as by screws l3, a hole being provided to allow the bearing 12 to project therethrough to receive the shaft 20. These bearings l9 and I2 are prefer- Each of these thrust bearings Ill and I2 (see Fig. 4) is accurately bored and machined to support the cylindrical bearings I l and I5 preferably constructed of carhon-chrome steel. These bearings are accurately bored to receive the reduced ends of the shaft and constitute bearings for this shaft 20 insofar as side thrusts are concerned. The top thrust bearing I2 is counter-sunk to receive a steel ball |1, whereas the lower thrust bearing H1 is drilled and threaded to receive the thrust screw it which through themedium of the steel ball l8 supports the lower end of the shaft 20. These balls l7 and I8 are preferably constructed of suitably hardened steel. This thrust screw "5 after once having been properly adjusted to lift the shaft 20 to an extent to snugly hold the upper bearing ball I? into its ball race, may be locked in position by tightening of the lock nut l9. From this construction it is seen that the entire weight of the shaft 20 and the apparatus supported thereby is supported by the lower steel bearing ball I8. This should not only reduce the rotational friction of the shaft 20 to a very low value but also should afford a large amount of Wearing surface in that this ball IE will be rotated from time to time and in so doing will expose new surfaces against the end of the shaft 2|! and the end of the thrust screw l6.

To this shaft 20 is secured, as by a pin 22, a spider 23, which spider supports the armature which is secured thereto, as by screws 26. To this armature 25 is fastened, as by screws 21, a balance wheel 30. In order to vary the total weight of the combined armature and balance wheel suitable weight rings 3| may be fastened to the balance wheel as by screws 32. It should be noted that these weight rings 3| are open or slotted at one side so that they may be passed around the shaft 20 without dis-assembling the shaft from its bearings. The total weight and total moment of inertia of the entire balance wheelabout its axis may therefore be varied by changing the number of weight rings which are screw fastened to the balance wheel, any number of weights being addable or subtractable from the apparatus without dis-assembling the shaft from its bearings. As shown, these rings 3| are assembled with the slots alternately at opposite sides, so that if two weights are added the wheel will remain in the same balanced condition but will of course be heavier. To the shaft 2|) is secured, as by a screw 33, a sleeve 34 to which the inner end of spiral spring 35 is secured as by a screw 35.

As readily seen from Fig. 4 the lower thrust bearing It, preferably made of brass, has its upper end machined to leave a cylindrical external surface and a shoulder. The radius arm 4|) (see Fig. l) is shaped at one end to constitute a bifurcated flanged band having a cylindrical internal surface. This cylinder has an internal dimension to receive the cylindrical portion of the thrust hearing If], the bifurcated end of the radius arm being clamped tightly on the cylindrical end of the thrust bearing (1 as by a screw 39. The free end of the radius arm 4|) is notched to receive the square head of a clamping bolt 4|, this bolt passing through a hole extending crosswise through the radius arm, as clearly shown in Figs. 3A and 3B. The square head of the clamping bolt 4| projects above the radius arm and is slotted or bifurcated to receive the end of the spiral spring 35. It will be noted that a rivet is passed through the extreme upper bifurcated end of the clamping bolt 4| crosswise of the slot, this in order to firmly clamp the spiral spring 35 against the radius arm when the nut 42 is firmly screwed against the radius arm 46.

It is readily seen that the vertically supported shaft 20, together with the balance wheel 30 and the spiral spring 35 constitute an oscillatory structure and that the period or frequency of oscillation of this structure may be varied by changing the effective length of the spiral spring 35, and that the effective length of this spiral spring 35 may be changed by loosening the clamping screw 4| sliding the end of the spiral spring 35 either into or out of the slot in the head of the clamping screw until the balance wheel oscillates at the proper frequency and by thereafter re-tightening the nut 42. It is also seen that the armature 25 may be properly centered to a diagonal position as shown in Fig. 2 by changing the adjustment of the radius arm with respect to its fixed support formed by the bearing In. This anchoring and adjustment construction enables the apparatus to be tuned to the proper frequency and for each frequency adjustment allows the balance wheel to be adjusted to its proper neutral or biased position. This construction is very quiet during operation because both of the ends of the spiral spring are firmly anchored so as to leave no lost motion between connected parts to cause impact, noise and wear. It is also readily seen that the moment of inertia of the balance wheel 30 about its axis may be changed by either adding or subtracting one or more of the open weight rings 3|.

To the shaft 25 are secured two cams 45 and at. The cam 45 when normal, that is when apparatus is at rest, engages the roller 41 to hold the contacts 48 and 49 closed. The cam 46, on the other hand, with the shaft 20 assuming its biasedat-rest position engages the rollers 50 and 5| in a manner to leave the front contacts 5253 and 5455 as well as the back contacts 56-51 and 5859 open. These contacts 52, 53, 54, 55, 56, 51, 58 and 59 are supported by an insulating support 5|] into which they are preferably moulded, this insulating support 60 preferably comprising suitable moulded material. In a similar manner the contacts 48 and 49 are supported by being moulded into a piece of insulating material 6|.

The upper free ends of the soft iron poles 5 and 6, namely, the portions which project through the upper or top plate of insulating material, are slotted at their ends to receive the ends of a core 55 of soft iron on which core is contained the actuating coil 66. The ends of the core 65 are flattened and may be firmly clamped in the slots 5 and 5 as by clampings screws 61.

After the effective length of the spiral spring 35 has once been determined through the medium of its adjustable connection to the free end of the radius arm 49, and after the desired weight of the balance by adding or subtracting weight rings 3| so as to cause oscillation of the balance wheel at the proper frequency, the armature 25 may be adjusted to its idle position as, for instance, illustrated by the solid lines in Fig. 2. This idle position is a diagonal position in which well within the air gap between the poles 5 and 6 but is at such angle that there is an appreciable air gap between the ends of this armature 25 and the pole faces 5 and B The interrupting cam 45 is preferably of such shape and is preferably so secured to the shaft 2i] that the contacts will open when the right-hand end (see Fig. 2) of the armature 25 assumes each of its two dotted positions. The contacts 48-49 are the armature 25 is wheel 35 has once been determinedopened when the right-hand end of the armature 25 reaches the dotted position 19 in order that the armature may continue to freely swing and oscillate at an appreciable amplitude. Upon the return stroke of the right-hand end of the armature 25 (see Fig. 2) the contacts 48-49 are not opened until this right-hand end of the armature 25 assumes the dotted position 1!. In fact, in ordinary practice the armature 25 very seldom reaches an amplitude extending to or going beyond the dotted position II. This latter break (at position 1|) in the circuit for the actuating coil 66 through the medium of the opening of contacts 48-49 is made to assure opening of this energizing circuit so that the right-hand end of the armature 25 will not be attracted by the lefthand pole piece (see Fig. 2). It is readily seen that if this opening of the contacts 48-49 at a position of the armature 25 at and beyond the position H were not provided for the righthand end of the armature 25 might actually be magnetically held permanently near the left-hand pole face 5*.

Referring now to Fig. 5 of the drawing, the oscillatory coder illustrated in Figs. 1-4 may be connected as illustrated in Fig. 5. It will be seen that the actuating coil 66 is included in series with a source of current such as a battery 13 and the interrupter contacts 48-49. It is also readily seen that the contacts 52-53 and 54-55 are connected in multiple and that the contacts 56-51 and 58-59 are connected in multiple. It

is also readily seen that the contacts 52-53,

54-55 are included in series with the track battery l5 and that the contacts 56-51, 58-59 when closed will shunt the track rails 16 together. In other words, the actuating coil 66 is intermittently opened by the actuating contacts 48-49 to maintain the oscillatory coder in operation and that during such operation the track circuit is alternately energized and alternately shunted by the closure of contacts 52-53, 54-55 and 56-51, 58-59, respectively. The circuit through the coil 66 is sufficiently inductive to cause a lag in flux acting on the armature to be sufiicient to produce a net torque in a direction to aid oscillation, namely, in a counter clockwise direction.

The applicant has thus shown and described one rather specific embodiment of his invention,

this having been done for the purpose of facilitating description of the invention and its principles of operation, and this should not be construed as a limitation of the invention; and it should be understood that various changes, modifications and additions may be made to adapt the invention to the particular problem encountered in practicing the same all without departing from the spirit or scope of the invention except as demanded by the scope of the following claims,

What I claim as new is:

1. In combination, in a motor, a base plate, a cylindrical thrust bearing, a vertical shaft for rotation in said thrust bearing, said bearing being supported on said base plate and having its upper cylindrical end reduced in diameter to leave a shoulder near its lower end, said shaft having its lower end within said thrust bearing, a spiral spring having its inner end secured to said shaft, a radius arm having one end swingingly adjustably secured to said reduced cylindrical end of said thrust bearing, and means for securing the free end of said radius arm to the outer free end of said spiral spring.

2. In combination, in a motor, a base plate, a cylindrical thrust bearing, a vertical shaft for rotation in said thrust bearing, said bearing being supported on said base plate and having an upper cylindrical end, said shaft having its lower end within said thrust bearing, a spiral spring having its inner end secured to said shaft, a radius arm having one end rotatably adjustably secured to said cylindrical end of said thrust bearing, and means for adjustably securing the free end of said radius arm to the outer free end of said spiral spring at various distances from the end of the spring so as to permit shortening or lengthening the eifective portion of said spring.

3. In combination, in a motor, a base plate, a cylindrical thrust bearing, a vertical shaft for rotation in said thrust bearing, said bearing being supported on said base plate and having its upper cylindrical end reduced in diameter to leave a shoulder near its lower end, said shaft having its lower end' within said thrust bearing, a spiral spring having its inner end secured to said shaft, a radius arm having its one end rotatably secured to said reduced cylindrical end of said thrust bearing, and means for adjustably securing the free end of said radius arm to the outer free end of said spiral spring at varying distances from the end of the spring in a manner to permit the shortening or lengthening of the effective part of said spring.

OSCAR S. FIELD. 

